1. Field of the Invention
The present invention relates to a vane pump for use in a power steering device.
2. Description of the Prior Art
As shown in FIG. 1, in a conventional vane pump, for use in a power steering of the type wherein a pair of side plates 6 and 7 are disposed within a pump housing 1 at opposite sides of a cam ring 5 receiving therein a pump rotor 3, in order to position the side plates 6 and 7 and the cam ring 5, a single positioning pin 13 is fitted at one end thereof into a boss portion 1c of the pump housing 1. The positioning pin 13 passes through an elongated hole 6b formed in the side plate 6 and a hole 5a formed in the cam ring 5 in fitted relation therewith. The other end of the positioning pin 13 is fitted into the side plate 7.
With this arrangement of the single positioning pin 13, the cam ring 5 has to be received in the pump housing 1 in fitted relationship therewith. This requires a grinding operation on the outer periphery of the cam ring 5 and causes the assembly of the cam ring 5 to be difficult. Furthermore, the axial width of an annular groove 10 leading to a pump reservoir is restricted, resulting in a lower suction efficiency.